1. Field of Invention
The present invention relates to a light module of a lighting device in a motor vehicle.
2. Description of Related Art
Various approaches for accomplishing so-called matrix high beam light modules are known in the prior art. A matrix high beam light module includes a light source with several semiconductor light sources (LEDs) which are arranged in rows and/or columns, where several LEDs are activated in order to produce the desired high beam light distribution. The individual LEDs can be activated individually, such that individual LEDs can be selectively deactivated, in order to specifically fade out certain areas of the resulting high beam light distribution. In this way, it is possible to cut out certain areas of the high beam light distribution, where other vehicles are located. This enables a particularly good illumination of the road way area in front of the motor vehicle with the high beam light distribution, and also prevents blinding other vehicles driving ahead of the vehicle and/or approaching. In order to create matrix high beam light modules, systems with an actual intermediate image are generally used, in which several directly joined images of the LEDs are produced by the primary optics, which are then reproduced on the roadway in front of the motor vehicle in order to produce the resulting high beam light distribution with a subsequent secondary optics within the optical path. Due to their projecting characteristics of the secondary optics, such systems are also called projection systems.
Suitable secondary optics are reflectors as well as lenses or lens systems. A secondary optics projects one or more light source images from an actual intermediate image layer onto the roadway in front of the motor vehicle in order to produce the desired light distribution of the light module. Suitable primary optics are, for example, converging lenses, conical light conductors, disc-shaped light conductors, or reflectors which can be arranged individually or in several rows and/or columns, array or matrix like, next to and/or above each other. When matrix semiconductor light sources are used, the primary optics generally includes lenses, light conductors, or reflectors which are combined to arrays. The light output area of the primary optics, or the light output areas of the individual primary optical elements of an optical array, is or are situated approximately within the so-called Petzval field curvature of the secondary optics, so that the individual light source images produced by the primary optical elements can be clearly delimited from each other with the help of refraction and/or reflection. The Petzval field curvature can be described as an area, where the points are reproduced as even as possible and in a desired way onto a distant image area in driving direction or in the direction of the beam with the secondary optics. Here, the object points can also be displayed as lines or rectangles or the like, instead of as points.
Depending on the type of primary optics that is being used in the prior art with this the light distribution, the intermediate image can only be minimally influenced in its shape and luminance distribution. Particularly arrays of converging lenses, whose light output area is arranged directly inside the Petzval field curvature of the secondary optics, produce light distributions with fairly uniform luminance. In such a case, the further light shaping (for example, the vertical shaping of the light distribution) has to be performed with a secondary optics, which features a distinctive astigmatism. Here, all light distributions in the intermediate image will be distorted in the same way by the subsequent secondary optics.
Most of the matrix light distributions include several equally wide strip-shaped light distributions in the center. In addition, it is meaningful to supplement these central light distributions with one or several wide light distributions at least towards the sides, which fade out softly towards the road side. If the particularly simple and preferred lens arrays or reflector arrays are used as primary optics, it is not automatically possible to produce one or more wide light distributions, which fade out softly towards the road side within the intermediate image and with which the described road side illumination can be created, directly adjacent to the fairly evenly illuminated light distributions in the center. In this case, the lens of the primary optics, which produces the intermediate image of the road side illumination, along with its assigned light source, would have to placed far behind (opposite to the light beam direction) the other light sources and lenses, which create an intermediate light distribution in the center of the matrix light distribution. With this, it would no longer be possible to arrange the light sources for the two light distributions (in the center on the one hand, and at the road side on the other hand) in one layer, preferably on one common circuit board, which significantly increases the engineering effort and the production costs of the light module. Furthermore, the repositioning of the light source(s) for the road side illumination to the back has an adverse effect on the construction length of the light module.
From US 2006/0120094 A1, a projection system for a lighting device in a motor vehicle is known, in which a low beam light distribution with a mainly horizontal cut-off line is supplemented by a partial high beam light distribution which illuminates an area above the cut-off line. The resulting high beam light distribution of the overall system is produced with an overlapping of the low beam light distribution and the partial high beam light distribution. The partial high beam light distribution is produced with the help of a light source and a concave mirror in an immediate image layer of the projection system. The high beam path is then deflected with a passive reflector through the secondary optics, which is designed as a projection lens whereby it is projected onto the roadway in front of the motor vehicle.